Pressure regulating means for aircraft instruments



Bin. 15, 1935. B. e. CARLSON PRESSURE REGULATING MEANS FOR' AIRCRAFT INSTRUMENTS Filed March 21, 1934 Aq I INVENTOR Bari 6. r2507? HIS 1%.? BY

l IE 5 DIRECTIONAL GYRO 1' AIR Pump Patented Jan. 15, 1935 1,987,666

UNITED STATES PATENT'OFFICE 1,987,666 PRESSURE BEGULATING MEANS FOR am- CRAFT INSTRUMENTS Bert G. Carlson, Queens Village, N, Y., assignor to Sperry Gyroscope Company, Inc., Brooklyn, N. Y., a corporation of New York Application March 21, 1934, Serial No. 716,671 3 Claims. (Cl. 137-153) This invention relates to pressure regulating nected to the interior of the pipe 7 leading to the means for supplying air at constant pressure to pump, as shown. At its center said diaphragm gyroscopic indicators on aircraft. At present is made to act as a valve to cooperate with a valve several of such indicators are usually employed, seat 16, as by being secured at its center to the including the turn indicator, directional gyroback of a valve 15 normally held on seat 16 by 5 scope, and the artificial horizon, in all three of means of a spring 17 which acts between the top which it is highly desirable that the speed of v of said valve and a collar 18 on an adjustable set rotation be maintained constant. Since the screw 19 threaded in the top of the member 12. speed of the aircraft engine and also the speed of Obviously the stiffness or compression of said the aircraft varies from time to time, it is obvious spring may be varied by adjusting said set screw 10 that the pressure supply would also vary'if driven 19 and locking it in place by means of the lock from the aircraft engine or supplied by means of nut 20. A" protectivecap 21 is shown over the a Venturi tube. In my invention I propose to set screw, The seat '16 of saidvalve is shown as interpose between the pressure supply and the securedto the top of a central boss 22 in the indicators a regulating valve for maintaining center of said base 6, which is open to the at- 15 the pressure substantially constant within fairly mosphere through a screen 23. g V wide limits. In this specification I use the term Obviously, as the pressure rises and falls in pipe pressure in the broad sense to include either 7, the pressure will also rise and fall in the chamsuper-atmospheric pressure or under-atmospheric ber 14, but at a slower or average rate due to pressure (vacuum), the latter being the system the small size of the restricted passage 24. It 20 most usually employed at the present time. should also be remembered that while the pres- Referring to the drawing showing one form sure in the chambers 13 and 14 is normally equal, my invention may assume, a greater pressure is exerted downwardly on the Fig. 1 is a diagram showingmyregulator placed piston 15 from chamber 14 than is exerted up- 25 between the vacuum pump and thegyroscopic wardly from the chamber 13 owingtothe fact that 25 t t the face of the piston is not in communication Fig. 2 is a vertical section of the regulating dewith the chamber 13 when closed. The central vice. portion of said face is, however, under atmos Fig. 3 is a bottom plan view of the same. pheric pressure whichis superior to that in cham- Fig. 4 is a section taken approximately on line' bers 13 and 14. If the spring 17 is adjusted so 0 4-4 in Fig. 2. as to said valve closed until the vac- In Fig. 1 the rectangle 1 may represent any uum or negative pressure in the chamber 14 beform of pressure producing means, such as a comes a predetermined amount, at that time' vacuum or pressure pump or Venturi tube, A said piston will open slightly and admit atmosplurality of air-driven gyroscopic instruments pheric air into the chamber 13, thus in-effect 35 shown at the right hand side of said figure, the lessening the pull on the pipes 3, 9 and 10 by turn indicator being shown at 2, the directional taking part of the air directly from the atmosgyro at 3, and an artificial horizon at 4. Between phere through the valve 15, 16 instead of all of the pump and said instruments I place my regsaid air being withdrawn from the instruments.

.40 ulating valve 5. As shown, said valve comprises when, however, a greater quantity of air pases 40 a base 6, into one side of which is tapped the through the pipe 7 owing to this influx of air pipe connection 7 leading to the pump 1. Into through the valve 15, 16, the pressure will the other side are tapped the pipe connections thus causing a rise in pressure in the chamber I 8, 9 and 10 leading to the gyroscopic instruments. 14, thus exe a greater downward pressure 4 If the instruments do not require the same preson the piston and closing the same. By caresure, this may be regulated by varying the size ful adjustment my valve may be niade to 'op-' of the bore in the respective pipes. Closing the crate within narrow limits so as to maintain the top of said base 6 is a flexible air-tight diavacuuminthe instruments substantially constant phragm 11, preferably of thin corrugated flexible in spite of wide variations in pump presure.

sheet metal. Said diaphragm is shown as Also, my valve not subject to polmding, chat- 50 clamped at its edges between said base and the tering or fluttering, as are devices of this top portion 12, thus providing'two chambers, 13 character, owing to the restricted character of below said diaphragm and 14 above said diathe passage 24 which averages or damps presphragm. I also provide a restricted opening 24 sure changes so that the valve is only responsive between the chambers 13 d 14. ;preferably conto a continued change of presure. 55

the apparatus which I now consider to repre-' sent-the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In a pressure regulating system for aircraft instruments, a device adapted to be placed be-- tween the pump and the instruments comprising a casing, aflexible diaphragm dividing the interior thereof into two chambers, one of which is in direct communication with the pump and instruments, and the other connected with the first chamber by a restricted passage, a valve seat associated with said diaphragmlessening the area thereof exposed to the pressure in said first chamber and exposing a limited area to atmospheric pressure, and spring means for holding said valve normally closed, whereby when the pressure differential on the instruments becomes more than. a predetermined amount, said valve opens to admit atmospheric air.

2. In a pressure regulating system for aircraft instruments, a device adapted to be placed between the pump and the instruments comprising a casing, means dividing the interior thereof into two chambers, one of which is in direct communication with the pump and instruments, and the other connected with the pump side of said first chamber, a valve seat associated with said means lessening the area thereof exposed to the pressure in said first chamberoand exposing a limited area to atmospheric pressure, and spring means for holding said valve normally closed, whereby when the pressure differential on the instruments becomes more than a predetermined amount, said valve opens to admit atmospheric air.

3. In a pressure regulating system for aircraft instruments, a differential valve in which one side is exposed to pump pressure through a restricted passage and the other side to atmospheric pressure, yielding means for maintaining said valve normally closed until the pump pressure differential exceeds a predetermined amount, and means for by-passing atmospheric air into the pump by the opening of said valve.

BERT G. CARLSON. 

